STUDY OF THE EXPRESSION AND FUNCTION OF THE TUMOR-ASSOCIATED ANTIGEN CAMBR1 IN SMALL-CELL LUNG CARCINOMAS

The expression of the epithelial antigen recognised by the MBrl monocl onal antibody (CaMBrl) was studied on 161 small cell lung carcinoma (S CLC) biopsies. A correlation between the marker expression and the ove rall survival of the patients was found. To investigate the possible r ole of CaMBrl in tumour aggressiveness, the in vivo and in vitro growt h capabilities of different SCLC cell lines, in relation to the antige n expression, were analysed. The CaMBrl-positive cell lines displayed a higher growth potential in comparison to CaMBrl-negative cells. The biochemical nature of CaMBrl was analysed in terms of enzyme sensitivi ty, molecular weight and comparison with other glycoproteins expressed by SCLC cells. The results indicated the trypsin sensitivity of the m olecule, and sialic acid hiding of the CaMBrl epitope. The increase of MBrl reactivity after neuraminidase treatment suggests that the CaMBr l epitope expressed in the SCLC cell line is carried by a sialoglycopr otein.